Surge on Sun

July 13, 2006

By Nick Lomb

Sunspots on the Sun indicate regions of strong activity and magnetic fields. The number of spots tends to vary with a cycle of 11-years called, not surprisingly, the sunspot cycle. In 2006 the Sun is at a minumum in the cycle and there are generally few spots visible. There are exceptions though. Over the last couple of weeks a large spot region numbered 898 moved across the Sun, going over the edge of the Sun about 12 July. The above image from NASA’s Solar and Heliospheric Observatory (SOHO) spacecraft indicates that the group was considerably larger than the Earth.

Monty Leventhal, a Sydney amateur astronomer from Sydney City Skywatchers observes the Sun regularly with special equipment that filters out all colours in sunlight except for a narrow band of colour associated with excited hydrogen atoms. On 5 July he photographed a surge – a jet of material ejected from an active region that reaches high into the Sun’s outer atmosphere or corona and then fades or returns along the same path. Monty’s image and details are as follows:

Filtergram taken on 5th July 2006 shows a large Surge below a Sunspot group in region 898.